1. Field of the Invention
The invention relates generally to radar and in particular to a height determining radar.
2. Description of the Prior Art
Radars are most typically used for determining the range of the target from the radar set. If the radar emits a narrow beam, the beam can be scanned in the azimuthal angle, i.e. around the vertical axis, to determine the azimuth of the target. By the same principle, if the beam width is narrow in both the azimuthal and polar directions, then the radar can be scanned in two dimensions to provide a determination of both the azimuth and elevation of the target. Such radars have been implemented to determine the height of radar targets. However the very narrow beam required for good resolution of altitude at long ranges necessitates antennas excessively large for mobile radars. Furthermore each sector of the two-dimensional scan must be individually probed thus increasing the time required for a complete scan in a search radar. Because aircraft radars and to lesser extent shipboard radars are not fixed in relation to the horizon, a determination of polar angle does not provide a direct determination of target elevation.